Revealing mistake: When Frank is unplugging the power cables from the T.V. He says "I will, I can, I am" you can see Greg mouthing those exact words at the exact same time. (00:16:50)
Continuity mistake: After Greg accidentally drops the bait in the lake because he was shocked that the bait was actually a worm, he puts his hands down but in the next shot his hand was at the same level of his chest. (00:18:45)
Continuity mistake: In the scene where Greg and Rowleys family are playing the game "I love you because..." the spinner they use keeps on changing positions in between shots. (00:42:00)
Other mistake: When Heather Hills takes a swing at Rodrick with mike stand and hits the chocolate fountain, how does Heather splash chocolate on herself?
Plot hole: When Greg gets caught faking his summer job, the receptionist tells his father that they don't employ minors, but Heather Hills who is sixteen (we know this because she is about to have her sweet sixteen) is a lifeguard at the pool.
Character mistake: When Greg reads the article about L'il Cutie being cancelled, cartoonist is misspelled cartoonish. The article also repeats the first column word for word in the third column.
Continuity mistake: Heather swings a mic stand at Rodrick. In the shot showing her getting splattered by chocolate, the stand disappears from her hands.
Factual error: When the boys get off the cranium shaker about ten people follow them out of the exit gate The ride only seats four.
Continuity mistake: When Greg dives into the pool, his hair is wet. In the next shot, he's still in the pool but his hair is completely dry, and when he goes to get Rodrick, his hair is wet again.
Continuity mistake: The part where Greg is holding Manny after washing his hands, you can see the pool isn't that packed, but when Frank tells Greg to swim and he walks in the pool, everyone is bunched up and it is packed.
Character mistake: When Greg notices his yearbook picture, the pictures of each student are in alphabetical order by last name. On the row Greg is on, the order is mixed up; The order is: Holly Hills, Wes Hamby, Greg Heffley, Rowley Jefferson. The order should have been Wes Hamby, Greg Heffley, Holly Hills, Rowley Jefferson.
Revealing mistake: In some of the shots where Greg is in the pool with no swimsuit on, you can see that he is wearing shorts in it before he asks the girl to give his swimsuit.
Continuity mistake: When Rodrick is showing Greg and Rowley the button at the Sweet 16, he has a jacket. However, in the next shot, he doesn't have a jacket, and then, in the following shot, his jacket is back on.
Continuity mistake: The time on the cranium shaker changes dramatically from 5 minute wait to when the boys get on and to 1 hour 10 minutes when they get off a few minutes later.
Continuity mistake: When Greg trips on the net, he tumbles on his front side. But in the next shot, he's on his back.
Answer: It is used after Greg tells Rodrick that Heather has accepted loded diper.